The Effect of Non-Pharmacological Treatment for Psychophysiological Insomnia on Cardiovascular Autonomic Regulation Assessed Using Heart Rate Variability

Background and ObjectiveaaCardiac autonomic regulation is altered in psychophysiological insomnia.We evaluated whether successful non-pharmacological treatment for psychophysiological insomnia could stabilize cardiac autonomic regulation.MethodsaaSubjects were 26 patients with psychophysiological insomnia who underwent four sessions of non-pharmacological treatment.We measured subjects' heart rate variability (HRV) at baseline and post-treatment.Based on the post-treatment Insomnia Severity Index (ISI) score, we categorized subjects into responder (n = 16, post-ISI < 8) and non-responder (n = 10) groups.ResultsaaAt baseline, we found no significant differences between responder and non-responder groups in age, sex, body mass index, insomnia severity, and features of HRV time and frequency domains.In the responders group, we observed significant increases in the standard deviation of the normal sinus to normal sinus interval (SDNN) (p = 0.02), the proportion of the number of interval differences of successive normal sinus to normal sinus intervals greater than 50 ms by the total number of normal sinus to normal sinus intervals (pNN50) (p = 0.02), total power (p < 0.01), and very low frequency (p = 0.02) and a significant decrease in low frequency (p = 0.04) after successful non-pharmacological treatment for insomnia.However, in the non-responders group, there were no significant changes in HRV features after treatment.ConclusionsaaThe successful non-pharmacological treatment of insomnia may reduce the risk of cardiovascular complications in patients with psychophysiological insomnia.